Current methods of predicting the amount of initial surgery needed to straighten the eyes of children with infantile (congenital) strabismus yield a success rate of no better than 70%. We hypothesize that the lack of success of the current method of prism cover measurement of the misalignment of the eyes is due in part to the method's failure to take into account the kinetic bias of the ocular motor system. This study will examine the relative contribution of a measure of the kinetic bias: the ability of a child with infantile strabismus to track an optokinetic stimulus moving in nasal and temporal direction under monocular viewing conditions. The ratio of optokinetic slow phase velocity to target velocity (gain) will be used as a predictor of surgical success.